Bibliography (4):

1. https://craigmod.com/essays/media_accounting/

2. https://www.robinsloan.com/newsletters/

3. https://lithub.com/do-yourself-a-favor-and-listen-to-robin-sloan-read-sir-gawain-and-the-green-knight/

4. Wikipedia Bibliography:

   1. https://en.wikipedia.org/wiki/Collimated_beam  :

      https://en.wikipedia.org/wiki/Collimated_beam